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From: ems@amdahl.UUCP (ems)
Newsgroups: net.space
Subject: Re: homemade railguns...
Message-ID: <2611@amdahl.UUCP>
Date: Mon, 20-Jan-86 14:31:58 EST
Article-I.D.: amdahl.2611
Posted: Mon Jan 20 14:31:58 1986
Date-Received: Tue, 21-Jan-86 09:00:15 EST
References: <8601171419.AA20243@s1-b.arpa>
Organization: Circle C Shellfish Ranch, Shores-of-the-Pacific, Ca
Lines: 25
Summary: How short a pulse is needed, anyway?

In article <8601171419.AA20243@s1-b.arpa>, dietz@SLB-DOLL.CSNET (Paul Dietz) writes:
> >Sorry, computer grade capacitors aren't of any use for
> >building railguns.  They have too much internal inductance
> >to supply the sort of short, high-current pulse that you
> >would need.  They won't even explode wires!  You might
> >have better luck with photo-flash capacitors charged to
> >an appropriately high voltage...
> 
> Rats!

Are you sure about this?  Just how short a pulse is needed, anyway?
I used 'computer grade' capacitors of about 20,000 mfd charged
to 20v or so to launch model rockets (circa 1972).  They did
a dandy job of vaporizing the nichrom wire igniters!  (Though
they did have enough charge left after the first launch to ignite
one, and sometimes two, additional rockets).

It was my understanding that rail guns took a fractional second
to a few seconds to accelerate something depending on design.
Surely a model could be built that would be able to use computer
grade caps?
-- 
E. Michael Smith  ...!{hplabs,ihnp4,amd,nsc}!amdahl!ems

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